I'm coming in on this thread late, and may have missed something,
Ueshiba, in his writings referred to irimi ("entering,") which really means taking the opponent's territory - occuping the space he is just moving into. In other words, an aikido atemi is irimi - placing your fist just where his face, for example, is trying to be. The second term Ueshiba used is "irimi-denkan." (The "D" is an alteration for ease of pronounciation, like a contraction.)

Ellis Amdur

It is tenkan with a 't' not a 'd' - maybe you got out of the wrong side of bed this morning